1. Field of the Invention
The present invention relates to a multipolar electrode lead of the type used with a medical apparatus for delivering electrotherapy, such as electrical stimulation pulses, in vivo to living tissue.
2. Description of the Prior Art
Medical electrode leads are generally known in the art which include an insulating sheath containing a coiled first conductor and a coiled second conductor which are coaxially arranged, with at least the first conductor being covered by an insulating coating so as to electrically separate the conductors from each other.
One such known electrode lead is disclosed in German OS 3 031 752. This known electrode lead contains a plurality of electrode conductors, each of which is provided with an insulating coating consisting of a polymer or the like to electrically separate the respective conductors. The insulated conductors are in the form of respective coiled conductors, disposed next to each other within the insulating sheath at the same distance from the center axis of the electrode lead.
After implantation in the vascular system of a patient, an electrode lead is flexed back and forth by movements of the body of the patient and blood vessels. The insulating polymer coating in the aforementioned known electrode lead could then rub off between two conductors, leading to a short-circuit.